The following warning message occurs: ""Unable to invoke type with no call signatures.". Code completion does not work. For example, it fails when I try o complete "app.g[et]"

Transpiling this file, however, works as expected.

Strangely enough, the warning message disappears and code completion works for a brief period of time (a few seconds), when I switch from "require('express');" to "module('express');" and then back to "require('express');". After
this brief period, the problems re-occur.

Any help would be greatly appreciated as I am really looking forward to start developing in TypeScript.

You can generally only call a module if what's returned from require is also callable. With the older .d.ts files, this would not be the case as they returned only a single module. With the newer compiler, there are typings that would let this work (using "export
=" in the .d.ts file, for example), but I'm not sure yet if your express.d.ts uses the new style.